In "Sonnet 12" the speaker suggests that the only solution to the destructive forces of time is to have children. But in "Sonnet 18" the speaker presents a second solution to the same problem.
"Sonnet 18" is probably the most famous of Shakespeare's sonnets. Although the poem does present the speaker's praise of beauty for the young man, the poem also presents love and the praise of beauty in such a general fashion that the poem could be applied to any man wishing to comment on the beauty of the lady he adores.
At this point the student may already be able to determine the structure of the poem with a quick glance at the lines. The perceptive reader will note that the third quatrain begins with the word but (in line 9). Thus, a logical assumption is that the shift in the poem occurs there; and so the sonnet can be divided between the octet and the sestet.
The sonnet begins with a question. The speaker is asking himself if he should compare the young man to a summer's day. The student should remember that a typical convention in love poetry is to use similes, to compare the beauty of the lady to the beauties of nature. As the poem progresses, we can see that the speaker feels that the answer to his question is "no" because he feels that the beauty of the young man is superior to the beauty of a summer's day. The comparisons, then, actually